CA2797488A1 - Magnetic-inductive flow meter - Google Patents
Magnetic-inductive flow meter Download PDFInfo
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- CA2797488A1 CA2797488A1 CA2797488A CA2797488A CA2797488A1 CA 2797488 A1 CA2797488 A1 CA 2797488A1 CA 2797488 A CA2797488 A CA 2797488A CA 2797488 A CA2797488 A CA 2797488A CA 2797488 A1 CA2797488 A1 CA 2797488A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/584—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters constructions of electrodes, accessories therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/588—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters combined constructions of electrodes, coils or magnetic circuits, accessories therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/14—Casings, e.g. of special material
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Measuring Volume Flow (AREA)
Abstract
A magnetic-inductive flow meter including a measuring tube, a magnetic circuit device, and two electrodes for detecting a measurement voltage. The measuring tube includes an inflow section, a measurement section that adjoins an inflow section, and an outflow section that adjoins the measurement section. A flow cross section of the measurement section is smaller than an inlet-side flow cross section of the inflow section and smaller than an outlet-side flow cross section of the outflow section. The electrodes are located on or in opposite electrode sections in the measurement section.
Description
MAGNETIC-INDUCTIVE FLOW METER
Background of the Invention Field of the Invention [0001] The invention relates to a magnetic-inductive flow meter with at least one measuring tube, at least one magnetic circuit device for implementing a magnetic circuit, and at least two electrodes for detecting a measurement voltage. The measuring tube has an inflow section, a measurement section, which adjoins the Inflow section, and an outflow section, which adjoins the measurement section. A flow cross section of the measurement section is both smaller than an inlet-side flow cross section of the inflow section and smaller than an outlet-side flow cross section of the outflow section. The electrodes are located on or in opposite electrode sections in the measurement section of the measuring tube, Moreover, the invention also relates to a measuring tube for a magnetic-inductive flow meter.
Description of Related Art 100021 The measurement enOneering foUndation for flow rate measurement with a conventional magnetic-inductive flow meter uses a measurement tube of a nonmagnetic material, for example, of a plastic or a nonmagnetic metal. The measuring tube is on a flow side in the region of the magnetic field generated by a magnetic circuit device.
The measuring tube is not electrically conductive or is insulated electrically from the measurement fluid by an insulating lining. In operation, the magnetic field generated by the magnetic circuit device permeates the measuring tube at a measurement section in a direction that is essentially perpendicular to the flow direction. If a measurement fluid with a minimum electrical conductivity is flowing through the measuring tube, charge carriers in the conductive measurement fluid are deflected by the magnetic field. The charge carriers create an electrical potential difference on electrodes which are located perpendicular to the magnetic field and to the flow direction. The charge carriers are detected with a measurement device and are measured as a voltage. The measured voltage is proportional to the flow velocity of the charge carriers which are moved with the measurement fluid such that the flow rate in the measuring tube can be deduced from the flow velocity.
Background of the Invention Field of the Invention [0001] The invention relates to a magnetic-inductive flow meter with at least one measuring tube, at least one magnetic circuit device for implementing a magnetic circuit, and at least two electrodes for detecting a measurement voltage. The measuring tube has an inflow section, a measurement section, which adjoins the Inflow section, and an outflow section, which adjoins the measurement section. A flow cross section of the measurement section is both smaller than an inlet-side flow cross section of the inflow section and smaller than an outlet-side flow cross section of the outflow section. The electrodes are located on or in opposite electrode sections in the measurement section of the measuring tube, Moreover, the invention also relates to a measuring tube for a magnetic-inductive flow meter.
Description of Related Art 100021 The measurement enOneering foUndation for flow rate measurement with a conventional magnetic-inductive flow meter uses a measurement tube of a nonmagnetic material, for example, of a plastic or a nonmagnetic metal. The measuring tube is on a flow side in the region of the magnetic field generated by a magnetic circuit device.
The measuring tube is not electrically conductive or is insulated electrically from the measurement fluid by an insulating lining. In operation, the magnetic field generated by the magnetic circuit device permeates the measuring tube at a measurement section in a direction that is essentially perpendicular to the flow direction. If a measurement fluid with a minimum electrical conductivity is flowing through the measuring tube, charge carriers in the conductive measurement fluid are deflected by the magnetic field. The charge carriers create an electrical potential difference on electrodes which are located perpendicular to the magnetic field and to the flow direction. The charge carriers are detected with a measurement device and are measured as a voltage. The measured voltage is proportional to the flow velocity of the charge carriers which are moved with the measurement fluid such that the flow rate in the measuring tube can be deduced from the flow velocity.
-2-100031 The sensitivity of the magnetic-inductive flow meter and the accuracy of the measurement which can be taken with the magnetic-inductive flow meter depend, among other things, on the magnetic field, which is generated with the magnetic circuit device in the region of the measurement section of the measuring tube, the geometry of themeasurement section and the arrangement of the electrodes. The geometry of the arrangement relates to the homogeneity of the magnetic field produced in the region of the measurement section, the flow conditions of the measurement fluid in the measthernerit section and, thus, also the electrical field generated by the charge separation in the measurement section,. which is the basis for the measurement The tuning of these different components of the magnetic-inductive flow meter to one another is crucial to attain accurate measurements.
[00041 Varying the cross section of the measuring tube beyond its longitudinal extension and, therefore beyond its extension in the flow direction is known from the .
conventional art. The in flow cross section of the inflow section conventionally has the geometry of the. process ponneetion Therefore, conventionally, a circular flow cross section having the nontinal width of lltepipe: in the pricos is connected to the magnetic-inductive flow Meter. The tOrieSpOnding applies :to the outlet,gle flow cross section of the outflow section, which likewise faees:the process... and 1.4101I owbe conoectext to the process. When "flow cross section" is addressed hoes it alWay'S mei* the free cross sectional area of the measuring tube which has been na*Itted perpendiMaatto the flow direction and which is available to the flow, therefore without the wall thicknessof, the pleasuria$ tube- at the pertinent site.
100051 German, Patent ApplicatiOn 1.0 2008 057 755 Al, which corresponds to U.S.
Patent 8,20,503 132, for example, diseloses that a flow cross section of an inlet-side end of an inflow section decreases toward a measurement section. and an outlet-side flow cross section of the measurement section. increases, in turn, to the outlet-side flow cross section of the outflow section of a- Incoming tube. The change of the cross section has the advantage that the flow velocity of the measurement fluid is increased in the region of the measurement section and, accordingly, a greater effect is also achieved for the charge separation as a result of the magnetic field in the measurement section.
00.61 The variable cross sectional geometry of the measuring tube beyond its longitudinal extension is achieved in the conventional art by comparatively complex production
[00041 Varying the cross section of the measuring tube beyond its longitudinal extension and, therefore beyond its extension in the flow direction is known from the .
conventional art. The in flow cross section of the inflow section conventionally has the geometry of the. process ponneetion Therefore, conventionally, a circular flow cross section having the nontinal width of lltepipe: in the pricos is connected to the magnetic-inductive flow Meter. The tOrieSpOnding applies :to the outlet,gle flow cross section of the outflow section, which likewise faees:the process... and 1.4101I owbe conoectext to the process. When "flow cross section" is addressed hoes it alWay'S mei* the free cross sectional area of the measuring tube which has been na*Itted perpendiMaatto the flow direction and which is available to the flow, therefore without the wall thicknessof, the pleasuria$ tube- at the pertinent site.
100051 German, Patent ApplicatiOn 1.0 2008 057 755 Al, which corresponds to U.S.
Patent 8,20,503 132, for example, diseloses that a flow cross section of an inlet-side end of an inflow section decreases toward a measurement section. and an outlet-side flow cross section of the measurement section. increases, in turn, to the outlet-side flow cross section of the outflow section of a- Incoming tube. The change of the cross section has the advantage that the flow velocity of the measurement fluid is increased in the region of the measurement section and, accordingly, a greater effect is also achieved for the charge separation as a result of the magnetic field in the measurement section.
00.61 The variable cross sectional geometry of the measuring tube beyond its longitudinal extension is achieved in the conventional art by comparatively complex production
- 3 -techniques, for example by casting a corresponding metal measuring tube, by internal high pressure forming or by injection molding of a plastic measuring tube. The production effort and the associated costs have, for a long time, prevented the use of magnetic-inductive flow meters for low cost, mass applications, for example as domestic weer meters. This is due not only to the production costs associated with the measuring tube, but also to the altogether comparatively demanding hardware and measurement-engineering structure of a magnetic-inductive flow meter.
Summary of the Invention 100071 The primary object of this invention is to provide a magnetic-inductive flow meter with a measuring tube in which a high measurement sensitivity and measurement accuracy are structurally supported, and, moreover, a measuring tube that is easily and thus economically producible.
[00081 The aforementioned object is achieved in a magnetic-inductive flow meter with a measuring tube in which a distance between the, electmde sections in the meastirement section of the me.asuring tube is greater Man thelargest inside diaineter of the hilet-skle flow cross section of the inflow section of the measuring tube. The distance between the electrode sections in the measurement section of the ineasuring tube means. the distance from wall to the wall of the measuring tube in the sections in which there are electrodes, regardless of the insulating linings of the measuring tube in this section, and also regardless of possible recesses in the measuring tube into which the electrodes are inlet When the inside diameter of the inlet side flow cross section of the inflow section is referred to herein, it is then assumed that the inlet-side flow cross section of the inflow section is the area of a circle. This results solely from the fact that magnetic-inductive flow meters must be connected to pipes with a circular cross section of the process system and, thus, in contrast to the flow cross section in the measurement section having circular or circular area flow cross sections and, thus, have only a single inside diameter there.
[0009] The great distance between the electrode sections in the measurement section of the measuring tube widens the distance available to charge separation beyond the amount that has been conventionally practiced, and, of added importance, the area over which a magnetic field can be introduced into the medium is increased beyond the conventional amount. This is
Summary of the Invention 100071 The primary object of this invention is to provide a magnetic-inductive flow meter with a measuring tube in which a high measurement sensitivity and measurement accuracy are structurally supported, and, moreover, a measuring tube that is easily and thus economically producible.
[00081 The aforementioned object is achieved in a magnetic-inductive flow meter with a measuring tube in which a distance between the, electmde sections in the meastirement section of the me.asuring tube is greater Man thelargest inside diaineter of the hilet-skle flow cross section of the inflow section of the measuring tube. The distance between the electrode sections in the measurement section of the ineasuring tube means. the distance from wall to the wall of the measuring tube in the sections in which there are electrodes, regardless of the insulating linings of the measuring tube in this section, and also regardless of possible recesses in the measuring tube into which the electrodes are inlet When the inside diameter of the inlet side flow cross section of the inflow section is referred to herein, it is then assumed that the inlet-side flow cross section of the inflow section is the area of a circle. This results solely from the fact that magnetic-inductive flow meters must be connected to pipes with a circular cross section of the process system and, thus, in contrast to the flow cross section in the measurement section having circular or circular area flow cross sections and, thus, have only a single inside diameter there.
[0009] The great distance between the electrode sections in the measurement section of the measuring tube widens the distance available to charge separation beyond the amount that has been conventionally practiced, and, of added importance, the area over which a magnetic field can be introduced into the medium is increased beyond the conventional amount. This is
- 4 -because, conventionally, pole shoes of the magnetic circuit device are provided on the wall sections of the measurement section which are perpendicular to the electrode sections in the measurement section of the measuring tube. This aspect of the invention increases the sensitivity of the magnetic-inductive flow meter in a geometrical-structural manner and improves the measurement accuracy since, at the distances between electrode sections disclosed herein, a largely. homogeneous magnetic field is produced over large parts of the volume in the measurement section.
[00101 In embodiments of the magnetic-inductive flow meter and its measuring tube in accordance with the aspects of invention, the flow cross section of the measurement section is essentially rectangular and has A length/width ratio of greater than 3:1 and, in implementations, greater than 3.5:1. In these length/width ratios, the length is defmecl as the distance between the electrode sections in the measUreinent Section of the measuring tube.
Implementations of this design stztndard result in an unusually flat flow chtmel which promotes flow conditions that have improved meaSureMent accurAcy. The short Walls which define the "width"
accommodate the electrode sections and .on -the ."Iong" walls, which are essentially perpendicular thereto there are, in implenientaions, ti* oppoQo rads f the root* circuit device.
Especially good results are achieved With implementations haying a length/width ratio of 3,741.
[00111 In ernhodinients of magnetic-indACtive flow meter and of the measuring tube for this flow meter, the -ratio of the inlet-side flow cross section of the inflow section to the flow cross section of the measmement section is greater Than 1.14:1, and, in implementations, greater than 2.0:1, and, in implementations, waiter than 22:1. It has been found that, at the large distance between the sections of the electrode in the measurement section of the measuring tube, a relatively speedy tapering of the flow cross section can be implemented without adversely affecting the flow in the measurement section of the measuring tube. This applies especially in conjunction with the aforementioned length/width ratio of the flow cross section in the measurement section.
100121 Embodiments of magnetic-inductive flow meter in accordance with aspects of invention are fimdamentally suited for use for all connection-side nominal widths, but are especially suitable for connection-side nominal widths of the measuring tube which are smaller than a 10 mm, and, in implementations, smaller than 40 mm. This is due to the fact that the
[00101 In embodiments of the magnetic-inductive flow meter and its measuring tube in accordance with the aspects of invention, the flow cross section of the measurement section is essentially rectangular and has A length/width ratio of greater than 3:1 and, in implementations, greater than 3.5:1. In these length/width ratios, the length is defmecl as the distance between the electrode sections in the measUreinent Section of the measuring tube.
Implementations of this design stztndard result in an unusually flat flow chtmel which promotes flow conditions that have improved meaSureMent accurAcy. The short Walls which define the "width"
accommodate the electrode sections and .on -the ."Iong" walls, which are essentially perpendicular thereto there are, in implenientaions, ti* oppoQo rads f the root* circuit device.
Especially good results are achieved With implementations haying a length/width ratio of 3,741.
[00111 In ernhodinients of magnetic-indACtive flow meter and of the measuring tube for this flow meter, the -ratio of the inlet-side flow cross section of the inflow section to the flow cross section of the measmement section is greater Than 1.14:1, and, in implementations, greater than 2.0:1, and, in implementations, waiter than 22:1. It has been found that, at the large distance between the sections of the electrode in the measurement section of the measuring tube, a relatively speedy tapering of the flow cross section can be implemented without adversely affecting the flow in the measurement section of the measuring tube. This applies especially in conjunction with the aforementioned length/width ratio of the flow cross section in the measurement section.
100121 Embodiments of magnetic-inductive flow meter in accordance with aspects of invention are fimdamentally suited for use for all connection-side nominal widths, but are especially suitable for connection-side nominal widths of the measuring tube which are smaller than a 10 mm, and, in implementations, smaller than 40 mm. This is due to the fact that the
- 5 -extension of the measurement section beyond the outside dimension of the inlet-side flow cross section between the electrode sections for magnetic-inductive flow meters of these sizes is not perceived as disruptive, since, for example, a housing can be easily produced to be so large that it also still encompasses the geometry of the measurement section which is discharging something. This may be a problem in magnetic-inductive flow meters with much greater nominal diameters.
[0013] In particular, there are now various possibilities for configuring and developing the magnetic-inductive flow meter according to aspects of the invention and the measuring tube for this flow meter according to aspects. of the invention. In this respect, reference is made to the description of exemplary embodiments in conjunction with the dmwings.
Brief Description of the Drawings [0014] Figure 1 shows a magnetic-induttive flowmeter, [0015] Figure 2 is a sectional view of a measuring tthe of the magnetic-inductive flow meter according to Figure 1, [0016] Figure 3 is a. sectional side view of the measuring tube according to Figure 2, and [0017] Figure 4 shows the cross section of the measurement section of the measuring tube according to Figures 1 to 3 in the regjon of the electrodes.
Detailed Description of the Invention [0018] Figure 1 shows a magnetic-inductive flow meter 1 with a measuring tube 2 and with a magnetic circuit device 3 for implementing a magnetic circuit and with two electrodes, of which only one electrode 4 is visible in the drawings. The electrodes 4 are used to detect a measurement voltage, which is established when a conductive medium is flowing through the measuring tube 2. Then, in the medium, a charge separation is established in the direction of the electrodes 4, when the magnetic circuit device 3 generates a magnetic field perpendicular to the flow direction and perpendicular to the imaginary axis of the opposing electrodes 4. In the exemplary embodiment shown in Figure 1, the magnetic circuit device 3 consists of two opposing pole plates 3a with one coil 3b each, which are energized by trigger electronics that are
[0013] In particular, there are now various possibilities for configuring and developing the magnetic-inductive flow meter according to aspects of the invention and the measuring tube for this flow meter according to aspects. of the invention. In this respect, reference is made to the description of exemplary embodiments in conjunction with the dmwings.
Brief Description of the Drawings [0014] Figure 1 shows a magnetic-induttive flowmeter, [0015] Figure 2 is a sectional view of a measuring tthe of the magnetic-inductive flow meter according to Figure 1, [0016] Figure 3 is a. sectional side view of the measuring tube according to Figure 2, and [0017] Figure 4 shows the cross section of the measurement section of the measuring tube according to Figures 1 to 3 in the regjon of the electrodes.
Detailed Description of the Invention [0018] Figure 1 shows a magnetic-inductive flow meter 1 with a measuring tube 2 and with a magnetic circuit device 3 for implementing a magnetic circuit and with two electrodes, of which only one electrode 4 is visible in the drawings. The electrodes 4 are used to detect a measurement voltage, which is established when a conductive medium is flowing through the measuring tube 2. Then, in the medium, a charge separation is established in the direction of the electrodes 4, when the magnetic circuit device 3 generates a magnetic field perpendicular to the flow direction and perpendicular to the imaginary axis of the opposing electrodes 4. In the exemplary embodiment shown in Figure 1, the magnetic circuit device 3 consists of two opposing pole plates 3a with one coil 3b each, which are energized by trigger electronics that are
- 6 -not detailed here. Likewise the magnetic closing of the magnetic circuit device is not explicitly shown.
[0019] Figures 2 to 4, in contrast to Figure 1, show only the measuring tube in order to emphasize its structural particulars.
[0020] In Figures 1 to 4, the measurement 2 has an inflow section 2a, a measurement section 2b adjoining the inflow section 2a and an outflow section 2c, which adjoins the measurement section 2b. As can be easily recognized, the flow cross section A
of the measuring tube. 2 changes greatly over the longitudinal octension of the measuring tube 2 and, therefore, in the tbroughi3ow direction. The flow cross section Am of the measurement section 2b is both smaller than the Wet-side flow cross section Ao. of the inflow section 2a and also smaller than the outlet-side flow cross section A. of the outflow section 2c.
t00211 The electrodes 4 are located on or in opposite electrode sections 5a, 5b in the measurement section 2b of the measuring tube 2, where they contact the electrical potentials arising due to charge separation and make them available as measurement voltage.
100221 As is especially apparent from Figure 3, the measuring tube 2 shown in the Op= is characterized in that the distarice sm between, t he electrode sections 5a, 5b in the measurement section 2b of the measuring tube 2 is larger than the inside diameter se, of the inlet-side .flow cross section A, of the inflow section 2a of the nieasining tube 2.
By the distance sm between the electrode sections 5a, 5b in the measurement section.2b being increased relative to the inside diameter so of the inlet-side flow cross section A.õ the distance of effective charge separation arid, thus, the effective measurement sensitivity of the magnetic-inductive flow .meter 1 is increased. At the same time, with the widening of the flow cross section, the possible supporting and action surface for the pole shoes 3a of the magnetic circuit device 3 is increased.
[0023] As can be clearly discerned from Figure 4, but as also follows from examining Figures 2 $c 3 together, the flow cross section Am of the measurement section 2b is essentially rectangular and, in this case, has a length/width ratio of roughly 3.7. The distance sm between the electrode sections 5a, 5b in this exemplary embodiment is, therefore, approximately four times greater than the height of the inside cross section. For a flow cross section Am of the measurement section 2b configured in this way, a favorable flow profile is achieved. This advantageously affects the attainable measurement accuracy. "Essentially rectangular" in this
[0019] Figures 2 to 4, in contrast to Figure 1, show only the measuring tube in order to emphasize its structural particulars.
[0020] In Figures 1 to 4, the measurement 2 has an inflow section 2a, a measurement section 2b adjoining the inflow section 2a and an outflow section 2c, which adjoins the measurement section 2b. As can be easily recognized, the flow cross section A
of the measuring tube. 2 changes greatly over the longitudinal octension of the measuring tube 2 and, therefore, in the tbroughi3ow direction. The flow cross section Am of the measurement section 2b is both smaller than the Wet-side flow cross section Ao. of the inflow section 2a and also smaller than the outlet-side flow cross section A. of the outflow section 2c.
t00211 The electrodes 4 are located on or in opposite electrode sections 5a, 5b in the measurement section 2b of the measuring tube 2, where they contact the electrical potentials arising due to charge separation and make them available as measurement voltage.
100221 As is especially apparent from Figure 3, the measuring tube 2 shown in the Op= is characterized in that the distarice sm between, t he electrode sections 5a, 5b in the measurement section 2b of the measuring tube 2 is larger than the inside diameter se, of the inlet-side .flow cross section A, of the inflow section 2a of the nieasining tube 2.
By the distance sm between the electrode sections 5a, 5b in the measurement section.2b being increased relative to the inside diameter so of the inlet-side flow cross section A.õ the distance of effective charge separation arid, thus, the effective measurement sensitivity of the magnetic-inductive flow .meter 1 is increased. At the same time, with the widening of the flow cross section, the possible supporting and action surface for the pole shoes 3a of the magnetic circuit device 3 is increased.
[0023] As can be clearly discerned from Figure 4, but as also follows from examining Figures 2 $c 3 together, the flow cross section Am of the measurement section 2b is essentially rectangular and, in this case, has a length/width ratio of roughly 3.7. The distance sm between the electrode sections 5a, 5b in this exemplary embodiment is, therefore, approximately four times greater than the height of the inside cross section. For a flow cross section Am of the measurement section 2b configured in this way, a favorable flow profile is achieved. This advantageously affects the attainable measurement accuracy. "Essentially rectangular" in this
- 7 -connection means than the flow cross section Am of the measurement section 2b is bordered for the most part by wall surfaces which run in pairs parallel to one another. The wall surfaces, however, pass into one another at the junction points only at a certain radius of curvature. The flow cross section Am of the measurement section 2b is unchanged in the exemplary embodiment shown here over the longitudinal extension of the measurement section 2b so that a smooth flow without tumecessary perturbations can be established in the measurement section 2b.
[00241 In the exemplary embodiment shown in the figures, the ratio of the inlet-side flow cross section fi1/4 of the Mow section. 2a to the flow cross section Am of the measurement section 2b is roughly 2.2. Therefore, a considerable reA]uction of the flow cross section results.
The illustrated structural layout is characterized in that the flow profile is, nevertheless, particularly suited for a high-quality flow rate raeciAllement.
100251 The inflow section 2a is shaped-such that it has a continuously decreasing flow cross secOon in a single coherent reducing region, Without sudden changes in cross section and vviihout phases remaining in a constant flow ctoss section. The same applies analogously, to the outflow section 2c, which in a single coherent exPansionsegion has a continuously increasing flow cross section which finally ends in the outlet side flow cross section A.
which is then kept constant over a short distance. However, this region of the constant outflow cross section As is no longer included in the expansion region.
100241 The configuration of the measurement section 2b Ofthe measuring tube 2 allows an especially short construction of the entire measuring tube 2. In the exempla!), embodiment shown in the figures the ratio of the longitudinal extension of the measurement section 2b to the longitudinal extension of the reducing region and the ratio of the longitudinal extension of the measurement section 2b to the longitudinal extension of the expansion region is settled at roughly 0.9 mm. The connection-side nominal width of the measurement tube 2 is 15 mm. The distance sm between the electrode sections 5a, 5b in the illustrated exemplary embodiment is 172 mm. The flow meter with the described dimensions is particularly useful, e.g., for registering water consumption in amounts conventional for households and, therefore, as a domestic water meter.
[00241 In the exemplary embodiment shown in the figures, the ratio of the inlet-side flow cross section fi1/4 of the Mow section. 2a to the flow cross section Am of the measurement section 2b is roughly 2.2. Therefore, a considerable reA]uction of the flow cross section results.
The illustrated structural layout is characterized in that the flow profile is, nevertheless, particularly suited for a high-quality flow rate raeciAllement.
100251 The inflow section 2a is shaped-such that it has a continuously decreasing flow cross secOon in a single coherent reducing region, Without sudden changes in cross section and vviihout phases remaining in a constant flow ctoss section. The same applies analogously, to the outflow section 2c, which in a single coherent exPansionsegion has a continuously increasing flow cross section which finally ends in the outlet side flow cross section A.
which is then kept constant over a short distance. However, this region of the constant outflow cross section As is no longer included in the expansion region.
100241 The configuration of the measurement section 2b Ofthe measuring tube 2 allows an especially short construction of the entire measuring tube 2. In the exempla!), embodiment shown in the figures the ratio of the longitudinal extension of the measurement section 2b to the longitudinal extension of the reducing region and the ratio of the longitudinal extension of the measurement section 2b to the longitudinal extension of the expansion region is settled at roughly 0.9 mm. The connection-side nominal width of the measurement tube 2 is 15 mm. The distance sm between the electrode sections 5a, 5b in the illustrated exemplary embodiment is 172 mm. The flow meter with the described dimensions is particularly useful, e.g., for registering water consumption in amounts conventional for households and, therefore, as a domestic water meter.
- 8 -[00271 In embodiments, the measurement tube 2 is made of a metal pipe of nonmagnetic material. The 'educing region of the inlet section 2a, the expansion region of the outlet section 2c, and the measurement region 2b are produced without cutting by forces acting from outside on the pipe. The pipe geometry can, therefore, be very easily produced without expensive production methods, such as casting or internal high pressure forming. As such, the production costs compared to conventional measuring tubes for the illustrated magnetic-inductive flow meters are very low and thus also a use of these niagnetic-inductive flow meters with these measuring tubes for mass applications in the low cost domain is possible.
f00181 Figures 1 to 3 show that the measunn' g tube 2 in the measurement section 2b bas a nonconductive lining 6 which can be omitted in other exemphuy embodiments in which the measuring tube itself is not electrically conductive.
f00181 Figures 1 to 3 show that the measunn' g tube 2 in the measurement section 2b bas a nonconductive lining 6 which can be omitted in other exemphuy embodiments in which the measuring tube itself is not electrically conductive.
Claims (19)
1. A magnetic-inductive flow meter comprising:
a measuring tube;
a magnetic circuit device;
at least two electrodes for detecting a measurement voltage;
wherein:
the measuring tube includes an inflow section, a measurement section adjoining the inflow section, and an outflow section adjoining the measurement section;
a flow cross section of the measurement section is smaller than an inlet-side flow cross section of the inflow section, and smaller than an outlet-side flow cross section of the outflow section;
the electrodes are located on or in opposite electrode sections in the measurement section of the measuring tube; and a distance between the electrode sections in the measurement section of the measuring tube is greater than an inside diameter of the inlet-side flow cross section of the inflow section of the measuring tube.
a measuring tube;
a magnetic circuit device;
at least two electrodes for detecting a measurement voltage;
wherein:
the measuring tube includes an inflow section, a measurement section adjoining the inflow section, and an outflow section adjoining the measurement section;
a flow cross section of the measurement section is smaller than an inlet-side flow cross section of the inflow section, and smaller than an outlet-side flow cross section of the outflow section;
the electrodes are located on or in opposite electrode sections in the measurement section of the measuring tube; and a distance between the electrode sections in the measurement section of the measuring tube is greater than an inside diameter of the inlet-side flow cross section of the inflow section of the measuring tube.
2. The magnetic-inductive flow meter recited in claim 1, wherein the flow cross section of the measurement section is rectangular and has a length/width ratio greater than about 3:1.
3. The magnetic-inductive flow meter recited in claim 2, wherein the length/width ratio is greater than about 3.5:1.
4. The magnetic-inductive flow meter recited in claim 2, wherein the length/width ratio is greater than about 3.74:1.
5. The magnetic-inductive flow meter recited in claim 1, wherein the flow cross section of the measurement section is unchanged over a longitudinal extension of the measurement section.
6. The magnetic-inductive flow meter recited in claim 1, wherein a ratio of the inlet-side flow cross section of the inflow section to the flow cross section of the measurement section is greater than about 1.8:1.
7. The magnetic-inductive flow meter recited in claim 6, wherein the ratio of the inlet-side flow cross section of the inflow section to the flow cross section of the measurement section is greater than about 2.0:1.
8. The magnetic-inductive flow meter recited in claim 6, wherein the ratio of the inlet-side flow cross section of the inflow section to the flow cross section of the measurement section is about 2.2:1.
9. The magnetic-inductive flow meter recited in claim 1, wherein the inflow section has a continuously decreasing flow cross section in a single coherent reducing region.
10. The magnetic-inductive flow meter recital in claim 1, wherein the outflow section has a continuously increasing flow cross section in a single coherent expansion region.
11. The magnetic-inductive flow meter recited in claim 1, wherein a ratio of a longitudinal extension of the measurement section to a longitudinal extension of a reducing region or the ratio of the longitudinal extension of the measurement section to a longitudinal extension a an expansion region is smaller than about 1.1:1.
12. The magnetic-inductive flow meter recited in claim 11, wherein the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the reducing region or the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the expansion region is smaller than about 1.0:1
13. The magnetic-inductive flow meter recited in claim 11, wherein the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the reducing region or the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the expansion region is smaller than about 0.9:1.
14. The magnetic-inductive flow meter recited in claim 11, wherein the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the reducing region or the ratio of the longitudinal extension of the measurement section to the longitudinal extension of the expansion region is smaller than about 0.89:1.
15. The magnetic-inductive flow meter recited in claim 1, wherein a connection-side nominal width of the measuring tube is smaller than about 40 mm.
16. The magnetic-inductive flow meter recited in claim 15, wherein the connection-side nominal width of the measuring tube is smaller than about 30 mm.
17. The magnetic-inductive flow meter recited in claim 15, wherein the connection-side nominal width of the measuring tube is about 15 mm.
18. The magnetic-inductive flow meter recited in claim 1, wherein the measurement tube
19. A measuring tube for a magnetic-inductive flow meter comprising:
an inflow section;
is made of a metal pipe of nonmagnetic material.
a measurement section that adjoins the inflow section;
an outflow section that adjoins the measurement section;
a flow cross section of the measurement section that is smaller than an inlet-side flow cross section of the inflow section and smaller than an outlet-side flow cross section of the outflow section; and recesses for electrodes in opposite electrode sections in the measurement section of the measuring tube, wherein a distance between the electrode sections in the measurement section of the measuring tube is greater than an inside diameter of an inlet-side flow cross section of the inflow section of the measuring tube.
an inflow section;
is made of a metal pipe of nonmagnetic material.
a measurement section that adjoins the inflow section;
an outflow section that adjoins the measurement section;
a flow cross section of the measurement section that is smaller than an inlet-side flow cross section of the inflow section and smaller than an outlet-side flow cross section of the outflow section; and recesses for electrodes in opposite electrode sections in the measurement section of the measuring tube, wherein a distance between the electrode sections in the measurement section of the measuring tube is greater than an inside diameter of an inlet-side flow cross section of the inflow section of the measuring tube.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102011119982.2 | 2011-12-02 | ||
| DE201110119982 DE102011119982A1 (en) | 2011-12-02 | 2011-12-02 | Magnetic-inductive flowmeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2797488A1 true CA2797488A1 (en) | 2013-06-02 |
| CA2797488C CA2797488C (en) | 2018-02-13 |
Family
ID=47594181
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2797488A Active CA2797488C (en) | 2011-12-02 | 2012-11-30 | Magnetic-inductive flow meter |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US9091574B2 (en) |
| EP (1) | EP2600119A1 (en) |
| JP (1) | JP5963660B2 (en) |
| CN (1) | CN103134558B (en) |
| CA (1) | CA2797488C (en) |
| DE (1) | DE102011119982A1 (en) |
| RU (1) | RU2594620C2 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012017904A1 (en) | 2012-08-21 | 2014-03-20 | Krohne Ag | Magnetic-inductive flowmeter and method for its manufacture |
| DE102014001479B4 (en) | 2014-02-06 | 2016-03-10 | Krohne Ag | Gastric table inductive flowmeter |
| DE102014111047B4 (en) | 2014-08-04 | 2016-02-11 | Endress+Hauser Flowtec Ag | Magnetic-inductive flowmeter with several measuring electrode pairs and different measuring tube cross-sections and method for measuring the flow |
| DE102014113404A1 (en) | 2014-09-17 | 2016-03-17 | Endress + Hauser Flowtec Ag | Magnetic-inductive flowmeter with a four-coil magnet system |
| DE102014113406A1 (en) | 2014-09-17 | 2016-03-17 | Endress + Hauser Flowtec Ag | Magnetic-inductive flowmeter with insert |
| DE102014113408A1 (en) | 2014-09-17 | 2016-03-17 | Endress + Hauser Flowtec Ag | Method for producing a magneto-inductive flowmeter with a partially reduced cross-section |
| DE102014119451A1 (en) * | 2014-12-22 | 2016-06-23 | Endress+Hauser Flowtec Ag | Magnetic-inductive flowmeter |
| DE102015116679A1 (en) * | 2015-01-14 | 2016-07-14 | Krohne Ag | Magnetic-inductive flowmeter |
| DE102015107119A1 (en) * | 2015-05-07 | 2016-11-10 | Endress + Hauser Flowtec Ag | Measuring tube and magnetic inductive flowmeter |
| DE102017110736A1 (en) * | 2017-05-17 | 2018-11-22 | Bürkert SAS | measuring device |
| DE102017115139A1 (en) * | 2017-07-06 | 2019-01-10 | Endress+Hauser SE+Co. KG | Measuring tube and measuring tube for determining and / or monitoring at least one process variable of a medium |
| IT201700112670A1 (en) * | 2017-10-06 | 2019-04-06 | Eltek Spa | SAFETY DEVICE AGAINST LIQUID LEAKS FOR LIQUID DUCTED HOUSEHOLD APPLIANCES |
| IT201700112704A1 (en) * | 2017-10-06 | 2019-04-06 | Eltek Spa | HYDRAULIC CONTROL DEVICE FOR LIQUID DUCTED APPLIANCES OR SYSTEMS |
| DE102018112897A1 (en) * | 2018-05-30 | 2019-12-05 | Krohne Messtechnik Gmbh | Magnetic-inductive flowmeter and measuring tube |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3387492A (en) * | 1966-05-02 | 1968-06-11 | Fischer & Porter Co | Magnetic flowmeters for low flow rates |
| GB2081449B (en) * | 1980-08-04 | 1984-09-26 | Aichi Tokei Denki Kk | Electromagnetic flow meters |
| DE3029791C3 (en) * | 1980-08-06 | 1994-08-04 | Aichi Tokei Denki Kk | Electromagnetic flow meter |
| JP2895704B2 (en) * | 1993-03-01 | 1999-05-24 | 株式会社オーバル | Ultrasonic flow meter |
| JP2001241981A (en) * | 2000-02-25 | 2001-09-07 | Toshiba Corp | Electromagnetic flowmeter |
| JP2002081976A (en) * | 2000-09-06 | 2002-03-22 | Yamatake Corp | Constriction structure of differential pressure type flowmeter |
| JP2005055276A (en) * | 2003-08-04 | 2005-03-03 | Yokogawa Electric Corp | Electromagnetic flowmeter |
| JP4591015B2 (en) * | 2004-02-19 | 2010-12-01 | 横河電機株式会社 | Electromagnetic flow meter |
| DE102008057756A1 (en) * | 2008-11-17 | 2010-05-27 | Krohne Ag | Magnetic-inductive flowmeter |
| DE102008057755B4 (en) * | 2008-11-17 | 2015-12-17 | Krohne Ag | Magnetic-inductive flowmeter |
| DE102008059067A1 (en) * | 2008-11-26 | 2010-06-02 | Krohne Ag | Magnetic-inductive flowmeter |
-
2011
- 2011-12-02 DE DE201110119982 patent/DE102011119982A1/en not_active Withdrawn
-
2012
- 2012-11-12 EP EP20120007664 patent/EP2600119A1/en not_active Ceased
- 2012-11-28 US US13/687,313 patent/US9091574B2/en active Active
- 2012-11-30 RU RU2012151374/28A patent/RU2594620C2/en active
- 2012-11-30 CN CN201210502362.1A patent/CN103134558B/en active Active
- 2012-11-30 CA CA2797488A patent/CA2797488C/en active Active
- 2012-12-03 JP JP2012264175A patent/JP5963660B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN103134558A (en) | 2013-06-05 |
| JP5963660B2 (en) | 2016-08-03 |
| JP2013117531A (en) | 2013-06-13 |
| EP2600119A1 (en) | 2013-06-05 |
| DE102011119982A1 (en) | 2013-06-06 |
| RU2012151374A (en) | 2014-06-10 |
| US9091574B2 (en) | 2015-07-28 |
| CN103134558B (en) | 2016-09-21 |
| US20130145861A1 (en) | 2013-06-13 |
| RU2594620C2 (en) | 2016-08-20 |
| CA2797488C (en) | 2018-02-13 |
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| EEER | Examination request |
Effective date: 20140930 |